Method of and apparatus for drying air.



D. BAKER.

METHOD OF AND APPARATUS FOR DRYING AIR.

APPLICATION TILED JUNE 21, 1907.

g Patented July 6, 1909.

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I q vdmeooco 5 DA VID BAKER, OF PHILADELPHIA, PENNSYLVANIA.

METHOD OF AND APPARATUS FOR DRYING AIR.

- Specification of Letters Patent.

Patented July 6, 1909'.

Application filed June 21, 1907. Serial No. 380,174.

' To all whom it may concern:

' such purposes.

.ductor and rapidly reducing t Be it known that I, DAVID BAKER, of Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented a new and useful Improvementin Methods of and App aratus for Drying Air, of which the followlng is a specification. v

This invention relates to the drying of air for use in connection with blast furnaces, Bessemer converters, or for other metallurgical purposes; and the invention consists of an improved process and apparatus for this urp'ose, whereby air of low constant humid- 1ty may be supplied in predetermined and uniform quantity.

The useof a blast of low humidity or dry air as it'is called, in the operation of blast furnaces, Bessemer converters, and the like, has-shown a very marked saving in the fuel consumption, and a large increase in the production of the furnace, but the cost of installation has prevented, so far, the general adoption of the ap aratus now employed for he cost of installation is due to the eat volume of air necessary to be cooled, an( the low temperature necessary in order to eliminate the moisture, and to the accumulation of frost or snow on the cooling surfaces or pipes in the refrigerating chamas a noncone efficiency of the device, and ren ering it necessary'to provide an extra cooling chamber, so that one could be thawed out while the other was in use. By my improved process, I overcome these objectionable features by compressing the air to be dried, so as to decrease the volume to be treated, and consequently the degree of temperature necessary to reduce the umidity to the desired point, the rise in hers, the layer of snow acting1 temperature of the air due to its compression being reduced by subjecting it to a primary cooling action, which may be conveniently effected by the use of the ordinary water supply always available at the blast furnaces or other Works. After this treatment, the partially cooled air is further reduced in temerature to bring it to the proper state of ow humidity suitable for use in the furnace blast, and in this condition the dried air is supplied to the furnace continuously in uniform unvarying quantity, so that the volume delivered for use in the furnace will be predetermined.

- In the accompanying drawings, I have represented a form of apparatus which I deem .vention into effect.

suitable for carrying my improved method into practice, but it will be understood that other forms may be employed for this purpose, provided the air is treated inthe manner described.

In the accompanying drawings :Figure 1 is an elevation partlyln section of an apparatus or plant suitable for carrying myv in- Fig 2 is a vertical cross section on the line a-a of Fig. 1. Fig.' 3 is a horizontal section on the line b'?) of Fig. 1.

A represents a blowing engine or compressor, bymeans of which the air to be treated is compressed.

B represents a cooling device which receives the air from the blowing engine through pipe at and subjects it to a primary cooling action to remove the heat which was developed by compression. C represents a second cooling device receiving the partially cooled air from the first cooler through pipe 0, and acting to further reduce its temperature to the proper degree for use in the furnace or converter.-

, D D represent a plurality of driers, though one only may be used, the construction of which is such as to tra or collect any moisture or water which may e mechanically suspended in the air after it leaves the cooler C. The air from cooler C enters the base of the driers through pipe d and leaves the top of the same through pipe E, which latter leads to the blast furnace G or the Bessemer converter F, or other point where the air is to be used, means bein provided, as will be more fully described ater on, whereby the supply of air for the furnace will be continuous and in known and unchanging measured quantity. v c

I The coolersB and C may be of any, appropriate construction for the ends in view. prefer, however, to construct them each in the form of a horizontal cylinder containing on its interior, perforated annular baffle plates 1, between which are :rotated perforated disks 2 fixed to a horizontal shaft 3, which shafts are mounted in bearings androceive motion from an suitablesource. The cylinders are partia filled with a cooling medium, so that as the perforated disks are rotated, the air forced through the cylinders above the water level, will be broken up into a multitude of streams, and will flow in intimate contact with the water in the v.form of films on the disks and bafiie plates, and will thus be very rapidly and efiectually cooled.

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In the first cooler, the function of which is to remove the heat developed by the compression of the air, water may be em loyed as the cooling agent, such as usua y available around blast furnaces, which water may enter the cylinder through inlet opening 6 and be discharged through outlet opening f- In the second cooler, however, it is necessary to reduce the temperature of the air considerably, in order to bring it to the proper degree of dryness, but it is not necessary to employ a freezing mixture for this purpose; hence I use in this second cooler a refrigerating mixture considerably higher in temperature than the freezing point, a temperature, say, of from 40 F. to 50 F. being sufficient to reduce the moisture content of the air to between one and two grains per cubic foot. By this second cooler, the temperature of the air is reduced and maintained at a constant point, and the air leaves the cooler at a constant temperature and pressure, however carrying wit it some fog or mechanically suspended water, which is removed by the action of the driers D D. These driers consist preferably of vertical cylindrical chambers containin screen-dis s 4 through which the air must pass in its upward flow to the point of exit, with the result that the moisture will be deposited on the surface of the disks. In the passage of the now thoroughly dried air to the furnace or converter, as the case may be, it is subjected to the action of a rotary blower or measurer H in the conducting pipe E, before alluded to. The function of this blower is to measure the air to the furnace or place of use, and cause it to be supplied in a continuous definite. and unvarying quantity, without regard to the resistance-offered to its flow throu h the apparatus. To effect this result, the lower or measurer His driven at a uniform speed controlled by a governor, and a uniform pressure is maintained on each side of the blower by pressure reducing valves I and K, the former being applied to pipe'a, and the latter being applied to the pipe leading from the blower to the furnace.

By this means, the pressure on each side of the blower II will be thefsame, so that the lat I ter will accurately measure or determine the quantity of air passing through it, and control the volume to be admitted to the fur nace. v

In the operation of the apparatus, the blower A is operated so as to subject the air to a definite predetermined pressure, higher than the greatest blast the furnace, this higher pressure being, say, fifteen pounds above atmospheric pressure,

any excess of which higher pressure being,

at intervals therein, horizontal.

ressure gbtammg at the point where the last enters.

through the second cooler C, the water in the blast is reduced to between one and two grains per cubic foot, due to the action of the refrigerating mixture at a temperature of 40 F. to 50F, thereby avoiding any formation of a nonconducting -surface of frost or snow. In its passage through the second cooler, the ,air blast becomes fog laden, holding water mechanically suspended, which, however, is removed by the passage of the air through the screen disks in the driers, the air leaving the driers in a state of low humidity ready for use at the blast furnace, or other place of ap lication. The nature of the apparatus whic I have described, admits of the amount of humidity in the air, which is finally delivered to the furnace, being controlled to a certain degree. Thus the regulation of the temperature of the water which is fed to the coolers B and C and the initial amount of compression given the air would modify the degree'of humidity, rendering it either practically dry or containing an appreciable amount of moisture, but once these conditions have become es tablished according to predetermination, I obtain for so long a time as I desire, a constant degree of humidity. The good effects of the air fed to the furnace are more the result of its regularity of quantity and composition than to the fact that the fluid contains a very minute quantity of moisture. In its passage to the furnace, the blower II running at a uniform speed, delivers the air continuously ata uniform pressure and constant humidity and in unvarying measured quantity, to the pipes leading to the furnace.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. The method of treating air for metallurgical purposes, which consists in compressing the same, reducing the temperature of the compressed air to remove'the heat developed by com ression, subjecting the air to a further cooling action to further reduce its temperature, maintaining the air in this condition at a constant pressure, and finally measuring and delivering the air thus treated to its lace of use,

2. The met 10d of treating air for metallurgical purposes, which consists in compressing the same, reducing the temperature of the com ressed air to remove the heat developed y compression, subjecting the air to a further cooling action, removing any mechanically suspended water carried by the air, maintaining the air at a constant piessure while being cooled and dried, and ally measuring and delivering the air thus tested under pressure to the place of use.

3. The method of treating airfor metallurgical purposes, which consists in compressing thesame, reducing the tem rature of the compressed 'air, maintainm the cooled air at constant temperature an pres-f sure, removing any water eld in sus ension, and delivering'the air thus treated to the placev of use.

4. The method oftreating air for metallurgical purposes, which cons sts in compressing the same, reducing the temperature of the compressed air, maintaining the cooled air at constant tem erature and pressure, removing any water eld in suspension,- and delivering to the furnace, air in measured quantities and containing a controllable amount of humidity.

5. The method of treating air for metal-v lurgical'purposes, which consists in compressing the same, reducin the temperature of com ressed air; w ereby its moisture is constant unva pressure, and delivering the air thus treate I to the place of use.

6. .The method of treating air and supply-' ing the same to blast furnaces, Bessemer converters" and the like, which consists in compressing the ,air, reducing the tempera .ture of the com ressed an, and measuring and supplying t e same for the furnace in definite unvarying'qua'ntity.

7. The method of treating ing the same to blast furnaces, Bessemer converters and thelike, which consists in compressing the air, reducing thetemperature of the 'com ressed air, and measuringandsup plying t e same to thefurnace in predetermlne quantity. ,8. Themethod of treating on and 'sup 1 inlglthe same to blast furnaces and the a e, v w

ch method consists'in. cqmpr the air, cooling the compressed air, malntai 7 the, same at a constant temperaturean pressure, and measuring and supplying the.

air for use in the furnace in unvarymgan definite quantity.

infil'the same to blast fumaces'bnd the 'ke, w ch method. consists in compress' the air, cooling the compressed air, maintainin the same. at a constant temperature an pressure, and measuring and supplying the air for use in the furnace in definite quantity,

I said air containing a'definite amount of humidity.

10. In an apparatus for treating and air and supply- 9. The method of treating air and sup ly-- suppl g the same to blast furnaces and the like, t e combination of means for compressing the air, means for reducing the temperature of the compressed air, means for'rnaintaming-the flow of the air through the appara'tus at constant and unchanging pressure, and means for'measuring the air flowing to the furnace.

11. In an apparatus for treating air and supplyl ling the same to blast furnaces and the like, t e combination of means for compressing the alr, means for reducing the temperature of the com ressed air, means for measu'ring the air flowm to the furnace, means for maintaining the ow of air to the measuring device at a 'constant and unchan ing pressure, and means for maintaining t e flow of air from the measuring device at a constant and unchanging pressure.

12. In an apparatus for drying air and supplying the same to blast furnaces and the like, a combination of means for compressing the air, means for reducingthe temperature of the compressed air, means for measuring the cooled air, and means for maintaining the flow of air for use in the. furnace at constant and predetermined pressure.

13. In an apparatus for treating air and supplying'the same to furnaces and the like, the com ination of. means'for compressing the air means for coolin the compressed air,

a pipe leading the coole air to the furnace, a

Lmeasurer in said pipe, and pressure controlling valves on op osite sides of themeasurer.

- I4. In anapparatus fordrying air and su plying the same to blast furnaces and tlEe 1 ke, a combination of means forcompressing the air, means for reducing the temperature of the compressed air, and means for delivering the air for use in thefurnace at a con stant pressure and in predetermined quan tityj 15. In anapparatus for drying air and su plying the same to' blast furnaces and t e ike, a combination of means for compressing the air, means for reducing the temperature -.of the compressedair, means for maintaining d the air at a constant pressure, and means for v.deliverin the air-for use 1n the furnace 1n measure quantities and containing a nite amountof humidit In testimony whereof l hereunto set my hand this 30th day of May, 1907, inthe presence of two attesting witnesses. h

, DAVID Witn: I B. Bi'mwna,

. M. ,Hunntrr; 

